Laser Direct Joining of Steel to Polymethylmethacrylate: The Influence of Process Parameters and Surface Mechanical Pre-Treatment on the Joint Strength and Quality

Abstract

The search for lightweight structures increases the demand for non-metallic materials, such as polymers, composites, and hybrid structures. This work presents the dissimilar joining through direct laser joining between polymethylmethacrylate (PMMA) and S235 galvanised steel using a pulsed Nd:YAG laser. The main goal is to determine the influence of processing parameters on joint strength and quality. In addition, the impact of surface conditions on the joint quality was also analysed. Overall, the optimum ranges of process parameters were found, and some are worth highlighting, such as the laser beam diameter and pulse duration, which significantly influenced the joint strength. Failure of the welded samples occurred in PMMA component, demonstrating good joint efficiency. Additionally, a maximum increase of 5.1% of the tensile shear strength was achieved thanks to the mechanical pre-treatment. It is possible to conclude that the joining between PMMA and the S235 galvanised steel can be performed by optimising the process parameters. Additionally, it can be enhanced through surface pre-treatments by exploring the mechanical interlock between both materials.

Fiber Laser Welded Cobalt Super Alloy L605: Optimization of Weldability Characteristics

“…In the inter-granular cleavage, micro-voids are seen at high and low energy input. The observed features show the ductile failure of the welded samples [ 42 , 43 ].…”

A Review on the Recent Trends in Forming Composite Joints Using Spot Welding Variants

“…LSW's process parameters are laser power, pulse duration, and laser beam diameter. The optimal laser peak power should be at 68-70%, as a lower power will create weaker joints and a higher peak power will cause the decomposition of the PMMA and the formation of bubbles at the interface [115]. The laser pulse duration has the most significant effect on the joint strength, followed by the laser peak power and welding speed [120,126,143].…”